Of private history: He was at Playford till Jan. 26th.--In April he went to c.o.c.kermouth to deliver his Lecture above-mentioned: the journey was by Birmingham, where he stayed for two days (probably with his son Osmund, who resided there), to Tarn Bank (the residence of Isaac Fletcher, M.P.): the lecture was delivered on the 22nd: he made excursions to Thirlmere and Barrow, and to Edward I.'s Monument, and returned to Greenwich on the 27th.--From June 17th to 28th he was at Playford.--From Aug. 19th to Sept. 17th he was travelling in Scotland, visiting the Tay Bridge, the Loch Katrine Waterworks, &c., and spent the last fortnight of his trip at Portinscale, near Keswick. On Dec. 23rd he went to Playford.

1879

"The ma.n.u.scripts of every kind, which are acc.u.mulated in the ordinary transactions of the Observatory, are preserved with the same care and arranged on the same system as heretofore. The total number of bound volumes exceeds 4000. Besides these there is the great ma.s.s of Transit of Venus reductions and ma.n.u.scripts, which when bound may be expected to form about 200 volumes.--With regard to the numerous group of Minor Planets, the Berlin authorities have most kindly given attention to my representation, and we have now a most admirable and comprehensive Ephemeris. But the extreme faintness of the majority of these bodies places them practically beyond the reach of our meridian instrument, and the difficulty of observation is in many cases further increased by the large errors of the predicted places.--After a fine autumn, the weather in the past winter and spring has been remarkably bad. More than an entire lunation was lost with the Transit Circle, no observation of the Moon on the meridian having been possible between January 8 and March 1, a period of more than seven weeks. Neither Sun nor stars were visible for eleven days, during which period the clock-times were carried on entirely by the preceding rate of the clock. The acc.u.mulated error at the end of this time did not exceed 0s'3.--Some difficulty was at first experienced with the Thomson Electrometer, which was traced to want of insulation. This has been mastered by the use of gla.s.s supporters, which carry some sulphuric acid. The instrument is now in excellent order, and the photographic registers have been perfectly satisfactory since 1879, February, when the new insulators were applied.--From the annual curves of diurnal inequality, deduced from the Magnetic Reductions, most important inferences may be drawn, as to the connection between magnetic phenomena and sun-spots. These annual curves shew a well-marked change in close correspondence with the number of sun-spots. About the epoch of maximum of sun-spots they are large and nearly circular, having the same character as the curves for the summer months; whilst about the time of sun-spot minimum they are small and lemniscate-shaped, with a striking resemblance to the curves for the winter months. The connection between changes of terrestrial magnetism and sun-spots is shewn in a still more striking manner by a comparison which Mr Ellis has made between the monthly means of the diurnal range of declination and horizontal force, and Dr R. Wolf's 'relative numbers' for frequency of sun-spots.--The records of sunshine with Campbell's Registering Sun-dial are preserved in a form easily accessible for reference, and the results are communicated weekly to the Agricultural Gazette.--Prof. Oppolzer's results for the determination of the longitudes of Vienna and Berlin, made in 1877, have now been made public. They shew a remarkable agreement of the Chronometric determination formerly made with the Telegraphic. It may be of interest to recall the fact that a similar agreement was found between the Chronometric and Telegraphic determinations of the longitude of Valentia.--For observing the Transit of Venus of 1882, the general impression appears to be that it will be best to confine our observations to simple telescopic observations or micrometer observations at Ingress and Egress, if possible at places whose longitudes are known. For the first phenomenon (accelerated ingress) the choice of stations is not good; but for the other phenomena (r.e.t.a.r.ded ingress, accelerated egress, r.e.t.a.r.ded egress) there appears to be no difficulty.--With regard to the Numerical Lunar Theory: Respecting the discordance of Annual Equation, I suspend my judgment. I have now discussed the theory completely; and in going into details of secular changes, I am at this time engaged on that which is the foundation of all, namely, the change of excentricity of the Solar Orbit, and its result in producing Lunar Acceleration. An important error in the theoretical formulae for Variations of Radius Vector, Longitude, and Lat.i.tude, was discovered; some calculations depending on them are cancelled."--Referring to the magnitude of the printed volume of "Greenwich Observations," and the practicability of reducing the extent of it, the Report states thus: "The tendency of external scientific movement is to give great attention to the phenomena of the Solar disc (in which this Observatory ought undoubtedly to bear its part). And I personally am most unwilling to recede from the existing course of magnetical and meteorological observations....The general tendency of these considerations is to increase the annual expenses of the Observatory. And so it has been, almost continuously, for the last 42 years. The annual ordinary expenses are now between 2-1/2 and 3 times as great as in my first years at the Royal Observatory.--Mr Gill was appointed to the Cape Observatory, and I wrote out instructions for him in March: there was subsequently much correspondence respecting the equipment and repairs of the Cape Observatory."--In the Monthly Notices of the Royal Astronomical Society for January an article had appeared headed "Notes on the late Admiral Smyth's Cycle of Celestial Objects, Vol. II." by Mr Herbert Sadler. In this article Mr Sadler had criticized the work of Admiral Smyth in a manner which Airy regarded as imputing bad faith to Admiral Smyth. He at once took up the defence of his old friend very warmly, and proposed certain Drafts of Resolutions to the Council of the Society. These Resolutions were moved, but were amended or negatived, and Airy immediately resigned his office of Vice-President. There was considerable negociation on the subject, and discussion with Lord Lindsay, and on May 9th Airy's Resolutions were accepted by the Council.--In October Airy inspected the "Faraday"

telegraph ship, then lying in the river near Messrs Siemens' works, and broke his finger by a fall on board the vessel.--In this year Airy wrote and circulated a letter to the Members of the Senate of the University of Cambridge, on the subject of the Papers set in the Smith's Prizes Examination. In this letter, as on former occasions, he objected much to the large number of questions in "purely idle algebra, arbitrary combinations of symbols, applicable to no further purpose." And in particular he singled out for comment the following question, which was one of those set, "Using the term circle as extending to the case where the radius is a pure imaginary, it is required to construct the common chord of two given circles." This drew forth as usual a rejoinder from Prof. Cayley, who wrote enclosing a solution of his problem, but not at all to Airy's satisfaction, who replied as follows: "I am not so deeply plunged in the mists of impossibles as to appreciate fully your explanation in this instance, or to think that it is a good criterion for University candidates."

Of private history: On Jan. 21st he returned from Playford.--On March 22nd he attended the funeral of his sister at Little Welnetham near Bury St Edmunds: Miss Elizabeth Airy had lived with him at the Observatory from shortly after his appointment.--For about a week at the end of April he was visiting Matlock, Edensor, and Buxton.--From June 14th to July 18th he was staying at Portinscale near Keswick.--He was at Playford for two or three days in October, and went there again on Dec. 23rd for his usual winter holiday.

The following letter, relating to the life of Thomas Clarkson, was written to Dr Merivale, Dean of Ely, after reading the account in the "Times" of October 10th of the unveiling of a statue of Clarkson near Ware:

ROYAL OBSERVATORY, GREENWICH, LONDON, S.E.

_1879, October 11_.

DEAR SIR,

Pardon my intrusion on you, in reference to a transaction which has greatly interested me--the honour paid by you to the memory of Thomas Clarkson. With very great pleasure I have heard of this step: and I have also been much satisfied with the remarks on it in the "Times." I well remember, in Clarkson's "History of the Abolition," which I read some 60 years ago, the account of the circ.u.mstance, now commemorated by you, which determined the action of his whole subsequent life.

It is not improbable that, among those who still remember Clarkson, my acquaintance with him began at the earliest time of all. I knew him, intimately, from the beginning of 1815 to his death. The family which he represented must have occupied a very good position in society. I have heard that he sold two good estates to defray the expenses which he incurred in his personal labours for Abolition: and his brother was Governor of Sierra Leone (I know not at what time appointed). Thomas Clarkson was at St John's College; and, as I gather from circ.u.mstances which I have heard him mention, must have been a rather gay man. He kept a horse, and at one time kept two. He took Orders in the Church; and on one occasion, in the course of his Abolition struggle, he preached in a church. But he afterwards resolutely laid aside all pretensions to the t.i.tle of Minister of the Church, and never would accept any t.i.tle except as layman. He was, however, a very earnest reader of theology during my acquaintance with him, and appeared to be well acquainted with the Early Fathers.

The precise words in which was announced the subject for Prize Essay in the University were "Anne liceat invitos in servitutem trahere."

After the first great victory on the slave trade question, he established himself in a house on the bank of Ullswater. I have not identified the place: from a view which he once shewed me I supposed it to be near the bottom of the lake: but from an account of the storm of wind which he encountered when walking with a lady over a pa.s.s, it seemed to be in or near Patterdale. When the remains of a mountaineer, who perished in Helvellyn (as described in Scott's well-known poem), were discovered by a shepherd, it was to Mr Clarkson that the intelligence was first brought.

He then lived at Bury St Edmunds. Mrs Clarkson was a lady of Bury. But I cannot a.s.sign conjecturally any dates to his removals or his marriage. His only son took his B.A. degree, I think, about 1817.

I think it was in 1814 that he began his occupation of Playford Hall--a moated mansion near Ipswich, formerly of great importance --where he lived as Gentleman Farmer, managing a farm leased from the Marquis of Bristol, and occupying a good position among the gentry of the county. A relative of mine, with whom I was most intimately acquainted, lived in the same parish (where in defiance of school rules I spent nearly half my time, to my great advantage as I believe, and where I still retain a cottage for occasional residence), and I enjoyed much of Mr Clarkson's notice. It was by his strong advice that I was sent to Cambridge, and that Trinity College was selected: he rode with me to Rev. Mr Rogers of Sproughton for introductory examination; he introduced me to Rev. C. Musgrave (subsequently of Halifax), accidentally doing duty at Grundisburgh, who then introduced me to Sedgwick, Peac.o.c.k, and T. Musgrave (subsequently of York). In 1825, when I spent the summer at Keswick, he introduced me to Southey and Wordsworth.

Mr Clarkson lived about thirty years at Playford Hall, and died there, and lies interred with his wife, son, and grandson, in Playford churchyard. I joined several friends in erecting a granite obelisk to his memory in the same churchyard. His family is extinct: but a daughter of his brother is living, first married to T. Clarkson's son, and now Mrs d.i.c.kinson, of the Rectory, Wolferton.

I am, my dear Sir, Very faithfully yours, G.B. AIRY.

_The Very Reverend, The Dean of Ely._

1880

"The Admiralty, on final consideration of the estimates, decided not to proceed with the erection of a new Library near the Magnetic Observatory in the present year. In the mean time the s.p.a.ce has been cleared for the erection of a building 50 by 20 feet.--I have removed the Electrometer Mast (a source of some expense and some danger), the perfect success of Sir William Thomson's Electrometer rendering all further apparatus for the same purpose unnecessary.--Many years ago a double-image micrometer, in which the images were formed by the double refraction of a sphere of quartz, was prepared by Mr Dollond for Capt. Smyth, R.N. Adopting the same principle on a larger scale, I have had constructed by Mr Hilger a micrometer with double refraction of a sphere of Iceland spar. Marks have been prepared for examination of the scale, but I have not yet had opportunity of trying it.--The spectroscopic determination of Star-motions has been steadily pursued. The stars are taken from a working list of 150 stars, which may eventually be extended to include all stars down to the fourth magnitude, and it is expected that in the course of time the motions of about 300 stars may be spectroscopically determined.--A new pressure-plate with springs has been applied by Mr Browning to Osler's Anemometer, and it is proposed to make such modification as will give a scale extending to 50 lbs. pressure on the square foot. Other parts of the instrument have also been renewed.--As regards the reduction of the magnetical results since 1863: In the study of the forms of the individual curves; their relations to the hour, the month, the year; their connection with solar or meteorological facts; the conjectural physico-mechanical causes by which they are produced; there is much to occupy the mind. I regret that, though in contemplation of these curves I have remarked some singular (but imperfect) laws, I have not been able to pursue them.--The mean temperature of the year 1879 was 46.1, being 3.3 below the average of the preceding 38 years. The highest temperature was 80.6 on July 30, and the lowest 13.7 on Dec. 7. The mean temperature was below the average in every month of the year; the months of greatest deviation being January and December, respectively 6.8 and 7.6 below the average; the months of April, May, July, and November were each between 4 and 5 below the average.

The number of hours of bright sunshine, recorded with Campbell's Sunshine Instrument, during 1879, was only 983.--In the summer of 1879 Commander Green, U.S.N., came over to this country for the purpose of determining telegraphically the longitude of Lisbon, as part of a chain of longitudes extending from South America to Greenwich. A successful interchange of signals was made with Commander Green between Greenwich and Porthcurno on four nights, 1879, June 25 to 29. The results communicated by Commander Green shew that the longitude of Lisbon Observatory, as adopted in the Nautical Almanac, requires the large correction of +8.54".--With regard to the coming Transit of Venus in 1882: From the facility with which the requirements for geographical position are satisfied, and from the rapid and accurate communication of time now given by electric telegraph, the observation of this Transit will be comparatively easy and inexpensive. I have attached greater importance than I did formerly to the elevation of the Sun.... I remark that it is highly desirable that steps be taken now for determining by telegraph the longitude of some point of Australia. I have stated as the general opinion that it will be useless to repeat photographic observations.

--In April Mr Barlow called, in reference to the Enquiry on the Tay Bridge Disaster. (The Bridge had been blown down on Dec. 28th, 1879.) I prepared a memorandum on the subject for the Tay Bridge Commission, and gave evidence in a Committee Room of the House of Lords on Apr. 29th." (Much of the Astronomer Royal's evidence on this occasion had reference to the opinions which he had expressed concerning the wind-pressure which might be expected on the projected Forth Bridge, in 1873.)--In May Airy was consulted by the Postmaster-General in the matter of a dispute which had arisen between the Post Office and the Telephone Companies, which latter were alleged to have infringed the monopoly of the Post Office in commercial telegraphs: Airy made a declaration on the subject.--In July Mr Bakhuyzen came to England to determine the longitude of Leyden, on which he was engaged till Sept. 9th, and carried on his observations at the Observatory.--In July Airy was much engaged in perusing the records of Mr Gill's work at the Cape of Good Hope.

Of private history: On Jan. 24th he returned from Playford.--From June 14th to July 4th he was again at Playford.--From September 21st to October 20th he was staying at Portinscale near Keswick.--On Dec. 23rd he went again to Playford for his winter holiday.

Respecting the agitation at Cambridge for granting University degrees to women, the following extract from a letter addressed to a young lady who had forwarded a Memorial on the subject for his consideration, and dated Nov. 10th, 1880, contains Airy's views on this matter.

"I have not signed the Memorial which you sent for my consideration: and I will endeavour to tell you why. I entirely approve of education of young women to a higher pitch than they do commonly reach. I think that they can successfully advance so far as to be able clearly to understand--with gratification to themselves and with advantage to those whose education they will superintend--much of the results of the highest cla.s.s of science which have been obtained by men whose lives are in great measure devoted to it. But I do not think that their nature or their employments will permit of their mastering the _severe_ steps of beginning (and indeed all through) and the _complicated_ steps at the end. And I think it well that this their success should be well known--as it is sure to be--among their relatives, their friends, their visitors, and all in whom they are likely to take interest. Their connection with such a place as Girton College is I think sufficient to lead to this. But I desire above all that all this be done in entire subservience to what I regard as _infinitely_ more valuable than any amount of knowledge, namely the delicacy of woman's character. And here, I think, our views totally separate. I do not imagine that the University Degree would really imply, as regards education, anything more than is known to all persons (socially concerned in the happiness of the young woman) from the less public testimonial of the able men who have the means of knowing their merits. And thus it appears to me that the admission to University Degree would simply mean a more extended publication of their names. I dread this."

1881

"The new line of underground telegraph wires has been completed by the officers of the General Post Office. The new route is down Croom's Hill in Greenwich, and the result of this change, at least as regards the earth-current wires, and probably as regards the other wires, has not been satisfactory. It was soon found that the indications of the earth-current wires were disturbed by a continual series of petty fluctuations which almost completely masked the proper features of earth currents.... If this fault cannot be removed, I should propose to return to our original system of independent wires (formerly to Croydon and Dartford).--The new Azimuth-mark (for the Altazimuth), upon the parapet of the Naval College, is found to be perfectly satisfactory as regards both steadiness and visibility. The observations of a low star for zero of azimuth have been omitted since the beginning of 1881; the mark, in combination with a high star, appearing to give all that is necessary for this purpose.--All the instruments have suffered from the congealing of the oil during the severe weather of the past winter, and very thorough cleaning of all the moving parts has been necessary.--The Solar Eclipse of 1880, Dec. 31, was well observed. The first contact was observed by four observers and the last contact by two. The computations for the observations have been exceptionally heavy, from the circ.u.mstance that the Sun was very low (86 14' Z.D. at the last observation) and that it has therefore been necessary to compute the refraction with great accuracy, involving the calculation of the zenith distance for every observation. And besides this, eighty-six separate computations of the tabular R.A. and N.P.D. of cusps have been required.--Amongst other interesting spectroscopic observations of the Sun, a remarkable spectrum of a sun-spot shewing 17 strong black lines or bands, each as broad as b_1, in the solar spectrum, was observed on 1880, Nov. 27 and 29. These bands to which there is nothing corresponding in the Solar Spectrum (except some very faint lines) have also been subsequently remarked in the spectrum of several spots.--The Police Ship 'Royalist'

(which was injured by a collision in 1879 and had been laid up in dock) has not been again moored in the river, and the series of observations of the temperature of the Thames is thus terminated.

--Part of the month of January 1881 was, as regards cold, especially severe. The mean temperature of the period January 12 to 26 (15 days) was only 24.2, or 14.7 below the average; the temperature fell below 20 on 10 days, and rose above the freezing point only on 3 days. The highest temperature in this period was 35.3, the lowest 12.7. On January 17th (while staying at Playford) my son Hubert and I noticed an almost imperceptible movement in the upper clouds from the South-East. On that night began the terrible easterly gale, accompanied with much snow, which lasted to the night of the 18th. The limiting pressure of 50 lbs. on the square foot of Osler's Anemometer was twice exceeded during this storm.--With respect to the Diurnal Inequalities of Magnetic Horizontal Force: a.s.suming it to be certain that they originate from the Sun's power, not immediately, but mediately through his action on the Earth, it appears to me (as I suggested long ago) that they are the effects of the attraction of the red end or north end of the needle by the heated portions of our globe, especially by the heated sea, whose effect appears to predominate greatly over that of the land. I do not say that everything is thus made perfectly clear, but I think that the leading phenomena may be thus explained. And this is almost necessarily the way of beginning a science.--In the first few years after the strict and systematic examination of compet.i.tive chronometers, beginning with 1856, the accuracy of chronometers was greatly increased. For many years past it has been nearly stationary. I interpret this as shewing that the effects of bad workmanship are almost eliminated, and that future improvement must be sought in change of some points of construction.--Referring to the Transit of Venus in 1874, the printing of all sections of the Observations, with specimens of the printed forms employed, and remarks on the photographic operations, is very nearly completed. An Introduction is begun in ma.n.u.script. I am in correspondence with the Commission which is entrusted with the arrangements for observation of the Transit of 1882.--The Numerical Lunar Theory has been much interrupted by the pressure of the Transit of Venus work and other business."--In his Report to the Board of Visitors (his 46th and last), Airy remarks that it would be a fitting opportunity for the expression of his views on the general objects of the Observatory, and on the duties which they impose on all who are actively concerned in its conduct. And this he proceeds to do in very considerable detail.--On May 5th he wrote to Lord Northbrook (First Lord of the Admiralty) and to Mr Gladstone to resign his post of Astronomer Royal. From time to time he was engaged on the subject of a house for his future residence, and finally took a lease of the White House at the top of Croom's Hill, just outside one of the gates of Greenwich Park. On the 15th of August he formally resigned his office to Mr W.H.M. Christie, who had been appointed to succeed him as Astronomer Royal, and removed to the White House on the next day, August 16th.

His holiday movements in the portion of the year up to August 16th consisted in his winter visit to Playford, from which he returned on Jan. 24th: and a subsequent visit to Playford from June 7th to 18th.

The following correspondence relating to Airy's retirement from office testifies in a remarkable manner to the estimation in which his services were held, and to the good feeling which subsisted between him and his official superiors.

10, DOWNING STREET, WHITEHALL, _June 6, 1881_.

DEAR SIR GEORGE AIRY,

I cannot receive the announcement of your resignation, which you have just conveyed to me, without expressing my strong sense of the distinction you have conferred upon the office of Astronomer Royal, and of the difficulty of supplying your place with a person of equal eminence. Let me add the expression of my best wishes for the full enjoyment of your retirement from responsibility.

I remain, dear Sir George Airy, Faithfully yours, W.E. GLADSTONE.

ADMIRALTY, _June 10th, 1881_.

SIR,

I am commanded by my Lords Commissioners of the Admiralty to acknowledge the receipt of your letter of the 4th instant, intimating your desire to retire on the 15th August next from the office of Astronomer Royal.

2. In reply I am to acquaint you that your wishes in this matter have been communicated to the Prime Minister, and that the further necessary official intimation will in due course be made to the Treasury.

3. At the same time I am instructed by their Lordships to convey to you the expression of their high appreciation of the remarkably able and gifted manner, combined with unwearied diligence and devotion to the Public Service (especially as regards the Department of the State over which they preside), in which you have performed the duties of Astronomer Royal throughout the long period of forty-five years.

4. I am further to add that their Lordships cannot allow the present opportunity to pa.s.s without giving expression to their sense of the loss which the Public Service must sustain by your retirement, and to the hope that you may long enjoy the rest to which you are so justly ent.i.tled.

I am, Sir, Your obedient Servant, ROBERT HALL.

_Sir G. B. Airy, K.C.B.

&c., &c., Royal Observatory, Greenwich._

ADMIRALTY, _28th June, 1881_.

SIR,

My Lords Commissioners of the Admiralty have much pleasure in transmitting copy of a resolution pa.s.sed by the Board of Visitors of the Royal Observatory on the 4th June last, bearing testimony to the valuable services you have rendered to Astronomy, to Navigation, and the allied Sciences throughout the long period during which you have presided over the Royal Observatory.

I am, Sir, Your obedient Servant, ROBERT HALL.